1. Field of the Invention
This invention relates generally to display devices and, more particularly, to a reflector used for a liquid-crystal display device.
2. Description of the Related Art
The reflective liquid-crystal display device, using a reflector for reflecting external light needs no backlight and advantageously reduce power consumption. The general reflective liquid-crystal display device has a liquid-crystal layer between the upper and lower substrates and a reflector on the upper or lower side of the lower substrate. The reflector has a plurality of unit reflecting portions that are concaves/convexes thereon to reflect and diffuse incident light.
The unit reflecting portions on the reflector are usually formed by photolithography. If the entire surface of a reflector is fabricated by one mask, huge data is required, which is costly. Accordingly, it is preferred to divide the surface of reflector into unit regions each of which has a certain arrangement of unit reflecting portions and repeatedly exposure, thereby fabricates one reflector.
By the way, in an attempt to randomly arrange unit reflecting portions, or concaves/convexes, within the unit region of the reflector, it is possible that concaves/convexes are not formed in some area (missing area). In case such a unit region having a missing area is arranged repeatedly, a line connecting the missing areas positioned with intervals is observed as a dark line by the viewer who sees the entire reflecting plate
It is also possible that convexes/concaves with little undulations are formed in some area (almost flat area) within the unit region. In case such a unit region having an almost flat area is arranged repeatedly, a line connecting the flat areas positioned with intervals is observed as a bright line by the viewer who sees the entire reflecting plate.
Furthermore, some convex/concave with certain shapes may differentiate the lightness observed in the different directions, thereby cause contrast, and some fringe-like pattern is observed. Such bright and dark pattern of the reflector deteriorates the quality of display when it is superposed on a display device.